Asymmetric Synthesis of trans-3-Amino-4-alkylazetidin-2-ones from Chiral N,N-Dialkylhydrazones
journal contributionposted on 05.08.2004, 00:00 by Elena Díez, Rosario Fernández, Eugenia Marqués-López, Eloísa Martín-Zamora, José M. Lassaletta
Enantiopure N,N-dialkylhydrazones 3 smoothly react with N-benzyloxycarbonyl-N-benzyl glycine as an aminoketene precursor to afford trans-3-amino-4-alkylazetidin-2-ones 4 as single diasteromers. As an exception, hydrazone 3f (R = OBn) affords cis-(3R,4R)-4f under modified conditions. N−N Bond cleavage of cycloadducts 4 afforded free azetidinones 5 in high yields.